A broad public perception that Republicans are offering the better-qualified candidates for president in 1988, particularly on national security and tax issues, is offsetting traditional Democratic advantages on domestic concerns and tilting the odds in the November election to the GOP, according to the latest Washington Post-ABC News poll.

Two weeks before the Iowa caucuses launch the nomination battle, two of every five Democrats surveyed say it would be better for their party to find another candidate to nominate at the convention than it would be to pick one of the seven men now actively campaigning.

Only one-tenth of the Republicans polled expressed similar dissatisfaction with their field of six contenders.

Among registered Republicans and Republican-leaning independents in the survey, Vice President Bush led Senate Minority Leader Robert J. Dole (Kan.) by 49 to 26 percent, similar to the edge he enjoyed in an October poll. Trailing in the poll completed Saturday were former television evangelist Pat Robertson, 8 percent; Rep. Jack Kemp (N.Y.), 6 percent, and former secretary of state Alexander M. Haig Jr. and former Delaware governor Pierre S. (Pete) du Pont IV, 4 percent each.

Among registered Democrats and independents who lean to the Democrats, civil rights leader Jesse L. Jackson and former senator Gary Hart (Colo.) led the field, with 25 and 23 percent respectively. The others were: Sen. Paul Simon (Ill.), l2 percent; Massachusetts Gov. Michael S. Dukakis, 11 percent; Sen. Albert Gore Jr. (Tenn.), 6 percent; Rep. Richard A. Gephardt (Mo.), 4 percent, and former Arizona governor Bruce Babbitt, 3 percent.

The national rankings differ markedly from recent polls in Iowa, which show Dole leading the GOP race and Gephardt, Simon and Dukakis out front among Democrats. History suggests that the national ranks will be radically reshuffled as the caucus and primary results come in.

More significant as early indicators of the 1988 political dynamic are the signs that despite their status as the minority party, the Republicans have achieved parity with the Democrats on issues and start with a "stature advantage" for their presidential candidates.

On the question of which party "you trust to do a better job in coping with the main problems the nation faces over the next few years," Republicans lead Democrats, 44 to 43 percent, regaining a parity they had lost during most of the 1987 surveys when the Iran-contra affair was so heavily in the news.

The voters at this point say they think the Republicans have done a better job than the Democrats in fielding their first team for the 1988 race. Seventy-five percent of the voters rate the Republican candidates well-qualified and only 59 percent make a similar judgment about the Democrats.

Only 21 percent of the whole sample, and just 10 percent of the Republicans, say they would like to see someone other than the active GOP candidates nominated. When it comes to the Democratic candidates, 45 percent of all voters and 39 percent of the Democratic voters would prefer to see someone else nominated.

That feeling shows up in many ways. Asked if they would vote for a Democratic or Republican candidate for president today, the registered voters in the survey split 46 to 41 percent Democratic. But by 56 to 38 percent, those same voters said they think the Republicans are the better bet to win in November.

Bush, the current GOP favorite, had commanding leads in trial heats against the top two Democrats. He led Hart by 53 to 39 percent and Jackson by 61 to 32 percent.

Personalities aside, the survey pinpointed sharp differences between the two parties' areas of strength. Large majorities believe a Democratic president would do a better job in helping the poor, meeting health care costs, creating more jobs and improving public education. The mythical Democrat has a slight advantage in handling the economy, reducing the trade and budget deficits, resisting demands from special interest groups and providing leadership for the country.

By a 2-to-1 ratio, these voters say a Republican president would do better in maintaining a strong national defense. Other areas of significant Republican advantage are in dealing with the Soviet Union, combating terrorism, negotiating further arms control agreements and holding down taxes.

The campaign debates so far have had limited audiences and impact, the poll suggests. Only 41 percent of the Democrats say they have watched their candidates debate and they rate Jackson by far the best of the performers. Dole and Bush are given identical top marks by the Republicans, 35 percent of whom say they have watched at least one debate.

Robertson and Haig have the highest unfavorable ratings among Republican voters -- 50 and 41 percent respectively -- and du Pont breaks even, with 13 percent favorable and unfavorable. Bush scores 70 to 20 percent favorable; Dole, 61 to 18, and Kemp, 33 to 13 percent. At least three out of five supporters of all the Republican candidates say their support is strong.

Hart is the only Democrat rated negatively by his fellow partisans, with a 47 to 42 unfavorable score. Jackson is 52 to 36 percent positive, and the others have more than half their fellow partisans unable to give an opinion. Their current scores are Simon, 33 to 10; Dukakis, 32 to 9; Gore, 20 to 11; Gephardt, 19 to 11, and Babbitt, 12 to 9 percent.

Among their own partisans, Jackson, Gore and Hart had the highest percentage of strong support- ers.

Polling editor Richard Morin and polling analyst Kenneth E. John contributed to this report.